fix(test): 契约测试解耦 stats-overhaul WIP(CI 抓到的真问题)

CI 暴露:我的契约测试引用了未提交的 stats-overhaul 文件,本地能过(文件在工作区)、
CI checkout 已提交代码就崩:
- api_contract_test.dart import device_usage.dart(?? 未提交)→ flutter analyze 报
  'Target of URI doesn't exist'
- usage/contract_test.go 引用 DeviceUsagePoint/deviceUsageResponse(HEAD service.go/
  handler.go 均无)→ go-server 编译失败
摘掉 /v1/usage/devices(DeviceUsage)契约,保留 /v1/me + /v1/usage(已提交)。
待 stats-overhaul 合并后再补 DeviceUsage 契约。
验证:flutter analyze test/contract 'No issues';go vet usage 无错。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/test/contract/api_contract_test.dart

@@ -1,17 +1,16 @@
 // api_contract_test.dart — HTTP API 契约快照(支柱 2:契约单源)。
 //
-// 冻结 /v1/me、/v1/usage、/v1/usage/devices 三个响应的「字段面」(snake_case JSON)。
+// 冻结 /v1/me、/v1/usage 响应的「字段面」(snake_case JSON)。
 // 字段增删改名会让本测试失败,逼开发者同步后端响应 + 文档,避免控制面与客户端悄悄分叉。
 //
 // ⚠️ 改下面的冻结集 = 改 HTTP 契约,必须同步:
-//   - 后端:server/internal/httpapi/account.go(/v1/me)、server/internal/usage/handler.go
-//     (/v1/usage、/v1/usage/devices)
-//   - 客户端:client/lib/models/{me,usage_point,device_usage}.dart
+//   - 后端:server/internal/httpapi/account.go(/v1/me)、server/internal/usage/handler.go(/v1/usage)
+//   - 客户端:client/lib/models/{me,usage_point}.dart
 //   - 文档:各 model 头注 + docs/dev-conventions.html 支柱 2
+// 注:/v1/usage/devices(DeviceUsage)契约待 stats-overhaul 合并后补(device_usage.dart 当前 WIP、未提交)。
 import 'package:flutter_test/flutter_test.dart';
 import 'package:pangolin_vpn/models/me.dart';
 import 'package:pangolin_vpn/models/usage_point.dart';
-import 'package:pangolin_vpn/models/device_usage.dart';
 
 // ── 契约冻结集(后端 snake_case JSON key)──────────────────────────
 const _frozenMeKeys = <String>{
@@ -31,15 +30,6 @@ const _frozenUsagePointKeys = <String>{
   'bytes_down',
   'minutes_used',
 };
-const _frozenDeviceUsageKeys = <String>{
-  'uuid',
-  'name',
-  'platform',
-  'bytes_up',
-  'bytes_down',
-  'minutes_used',
-};
-
 Map<String, dynamic> _meSample() => {
       'email': 'me@example.com',
       'plan': 'pro',
@@ -59,15 +49,6 @@ Map<String, dynamic> _usagePointSample() => {
       'minutes_used': 12,
     };
 
-Map<String, dynamic> _deviceUsageSample() => {
-      'uuid': 'dev-uuid-1',
-      'name': 'MacBook',
-      'platform': 'macos',
-      'bytes_up': 3000,
-      'bytes_down': 4000,
-      'minutes_used': 30,
-    };
-
 void main() {
   group('/v1/me 契约快照', () {
     test('字段面冻结(增删字段须同步后端 account.go + 文档)', () {
@@ -103,21 +84,4 @@ void main() {
       expect(p.bytesTotal, 3000);
     });
   });
-
-  group('/v1/usage/devices 契约快照(DeviceUsage)', () {
-    test('字段面冻结', () {
-      expect(_deviceUsageSample().keys.toSet(), _frozenDeviceUsageKeys);
-    });
-
-    test('fromJson 正确解析 + 派生', () {
-      final d = DeviceUsage.fromJson(_deviceUsageSample());
-      expect(d.uuid, 'dev-uuid-1');
-      expect(d.name, 'MacBook');
-      expect(d.platform, 'macos');
-      expect(d.bytesUp, 3000);
-      expect(d.bytesDown, 4000);
-      expect(d.minutesUsed, 30);
-      expect(d.bytesTotal, 7000);
-    });
-  });
 }

server/internal/usage/contract_test.go

@@ -57,14 +57,5 @@ func TestContractUsagePoint(t *testing.T) {
 	)
 }
 
-func TestContractDeviceUsagePoint(t *testing.T) {
-	assertFrozenKeys(t, "/v1/usage/devices DeviceUsagePoint", jsonTagSet(DeviceUsagePoint{}),
-		"uuid", "name", "platform", "bytes_up", "bytes_down", "minutes_used",
-	)
-}
-
-func TestContractDeviceUsageResponse(t *testing.T) {
-	assertFrozenKeys(t, "/v1/usage/devices envelope", jsonTagSet(deviceUsageResponse{}),
-		"devices",
-	)
-}
+// 注:/v1/usage/devices(DeviceUsagePoint + deviceUsageResponse)契约待 stats-overhaul
+// 合并后补——这两个 struct 当前是未提交 WIP,引用它们会让 CI 编译失败。